Mercury switch flow interlock



G L USSELMAN HEHCURY SWITCH FLOW INTERLOCK Filed Jan. 25, 1936 2 Sheets- Sheet l CONTACTS INVENTOR. GEORGE L. USSELMAN ATTORNEY.

Patented Feb. 21, 1939 I I UNITED STATES PATENT OFFICE 2,148,395 MERcuRY swrrcn FLow m'rnanocx George Lindiey Usselman, Port Jefferson, N. Y., assignor to Radio Corporation of America, a corporation of Delaware Application January 25, 1936, Serial No. 60,788

8 Claims. (01. 200-81) This invention relates to an improved mercury by means of a plurality of metallic rods which switch flow interlock which is particularly are threaded at I! in base 1 and secured at the adapted to a radio transmitter of large capacity. upper portion thereof to member III by means An object of this invention isto provide a reof suitable screws l3. Centrally located within liable, simple and rugged switch for breaking an base 1 is a rod ll which is threaded at I to reelectrical circuit when a normally continuous tain a solid valve or flow interlock element i6 flow of liquid ceases and for closing said circuit substantially cone-shaped at the portion which when there is normal flow of liquid. normally rests upon the seat 5. It will be noted The mercury switch flow interlock of this inthat the orifice is formed by seat 5, and the 10 vention is generally used in connection with shape of the plung r the Particular shape some control circuit having relays or contacts shown in Figures 1 and 4 i f r ffl i p which handle the breaking and making of the tion of large liquid flows, in the order of 8 to larger currents and voltages of a radio transmitgallons per minute. The size, weight and curvater. The liquid flow interlock ishormally placed ture of the plunger may be changed to suit the 15 in the outlet pipe of the apparatus to be proflow of liquid used. Because oi. being used in a 15 tected for example, in a water" cooled-vacuum relatively large flow in this interlock, a large tube. The power being removed from the appaorifice is used and the curvature of the plunger ratus in an electrical circuit by the switchwhen cone is relatively small. This gives sufllcient the liquid flow is stopped or falls below alcer -m lifting force without retardlng'the liquid flow tain predetermined value. The flow interlock of to any great extent. Suitably located on the 20 this invention is briefly a chamber in which there top member III are two supporting rods 11 and is provided a valve seat or nozzle for causing one Of these rods Serves the due-1 P p the liquid to form a fountain-like flow which is of acting as. electrical terminals for the switch suflicient in pressure to raise a solid floating and also supporting and guide members of the member of substantial weight having a rod-like switch- The Sw 9 is a e y Switch. T 25 end to operate a small pivoted mercury switch. w t is pr y of h typ hav n a p The solid floating member is arranged with a of contacts u y arranged Within a glass nspecial contour similar to a water turbine bucket closure a contains a Small q y of to function with as little retardation to the flow y- When the Switch is Placed in a horizontal of the liquid as possible. position the mercury causes the contacts to be 30 The invention will best be und r to d by r short circuited and thus completes a short cirferring to the accompanying drawings in whi h; cult between them. When-the switch is tilted on Figure 1 is a section of the improved flow inan angle the c y W away from t e conterlock, tacts and thus opens the electrical circuit. In 5 Figure 2 is a, side view partly in se tion of order to provide'a sensitive and rugged support 5 Fig. 1, a for the mercury switch a cradle-like member 20 Figure 3 is a plan view of Figures 1 and 2, is p p u y Supperted upon the pp Figure 4 is a, detailed ection showing a, poring rods l1 and I8. One of the rods [8 is protlon of Figures 1 and 2, vided with a slot 2| in which a projecting mem- 40 Figure 5 is a detailed ection sho ing v 1 ber 22 onthe cradle 20 is arranged to engage and 40 for small liquid flows, prevent the cradle from tilting beyond the cor- Referring now in detail to Figures 1 and 2, rect angle. At the lhwer end of rods I1 and I8 the metallic flow chamber l is provided with n insulating m nd de member 23 is sepipe threaded ends 2 and 3 for coupling-the ed by screws 24 and This ber uides chamber with circulating liquid. Substantially od 14 and a p ts a n ency of the 45 in the center of the chamber there is located an q d flowing l Chamber 1 to splash p orifice 4, the top of which is provided with a into the Zone Where the mercury Switch s 10- valve seat 5. Directly above the orifice an en cated. Electric connections from the merlarged box-like portion 6 which is provided for cury switch S9 is made b means of two flexible receiving the metallic base i of a housing 3. leads 25 and 23. These flexible leads are pro- 5() The housing 8 comprises a cylindrical wall a, vided with suitable flexible insulating members preferably of transparent glass, The housing 8 such as glass beads 23 and lead 21 is connected is closed at the top by an insulated member in from the lower terminal portion of the mercury of any suitable insulating material suclras Bakeswitch to rod 9 8, the upper portion of rod 88 ilte. Members 9 and iii are secured to base i being provided with suitable terminals, nuts 29 and 3d and washers 8i and 32. The lead 28 is connected from switch is to a terminal screw 8% and terminals nuts 89 and db and washers di and d2.

In Figure 4 there is shown partly in section, the operating portion of the member it. It will be noted that when the switch is is closed the projecting tongue of the cradle is arranged to touch the stop 2! before the mercury switch touches the glass cylinder wall. Also the valve will be fully open when the switch is closed. In order that the upper portion of rod l6 will be electricaily insulated from the switch cradle 2d, a glass rod preferably of Pyrex glass rod 32 is provided. This rod is rounded over at the top 3% and provides a convenient and good wearing bearing for actuating the switch through a member 35. The entire housing is made air tight by means of suitable gaskets 35 and ti which are compressed between members TI, a and it by means of screws l3.

The fiow interlock shown in Figure 5 is particularlyadapted for smaller fiows of liquid. As mentioned above, it he desirable to have the interlockiunction with-as'little retardation to the how of liquid as possible. Likewise, with a normal how of liquid the plunger must push upward with enough force to hold the mercury switch it in the closed or horizontal position. .To ob tain these results the sizeof the orifice and the curvature of the cone portionjoi the interlock and its weight must be correctly selected. The flow interlock 38 shown in Figure 5 is particularly adapted for small flows oi liquid such as those in the order of l to 2 gallons per minute. In this type of interlock the orifice is made adjust= able by means of providing difierent nozzles fill which are threaded at all to the webbed portion cone shaped face is greater. This gives large fting force for the small liquid flows.

Both types of interlocks shown in Figures 1 andd are arranged with adjustable features so that a normal fiow of liquid will hold up the plungers it and it and maintain the mercury switch is in a closed position; also when the liquid fiow drops to approximately one-half that of normal or less the plungers will drop sumcientiy to open the mercury switch.

While only two embodiments of this invention have been disclosed, it is to be distinctly under stood that this invention is not to be limited by those shown, but only by such limitations as are clearly imposed in the appended claims.

I claim:

1. A liquid fiow interlock comprising an enclosing chamber, an orifice within said chamber, a cylindrical glass housing above said orifice, a rod supported within said housing, an insulating disc located above said cylindrical glass housing and having secured thereto electrical terminals, :5. floating member secured to the lower end of said rod, a pivoted enclosed liquid conducting switch located above said rod so as to break an electrical circuit when the normal flow of the liquid decreases to a predetermined value.

2. A liquid flow interlock comprising an enclosing chamber, an orifice within said chamber, a housing above said orifice, a rod supported within said housing, a solid floating member secured to the lower end of said rod, an insulating disc located at the top of said housing, two depending rods supported from said insulating disc, a pivoted enclosed liquid conducting switch begreases ing arranged so as to break an electrical circuit when the normal flow oi the liquid is reduced to a predetermined value.

3. A liquid flow interlock comprising an .enclosing chamber, an orifice within said chamber, a housing above said orifice, a rod supported within said housing, a solid floating member analogousto a water turbine bucket secured to the lower end of said rod, an insulating disc located at the top of said housing, two depending rods supported from said insulating disc, a mercury switchhaving flexible leads electrically con nected to said depending rods, a pivoted enclosed liquid conducting switch being arranged so as tobreak an electrical circuit when the nol fiow of the liquid ceases.

d. A liquid now interlock comprising an enclos a rod supported within saidhoining, a solid fioating deflecting member secured to the lower end of said rod, an insulating disc located at the top of said housing, two depending rods supported from said insulating disc, a cradle-like member pivoted to at least one of said rods and supporting an enclosed liquid conducting switch, said cradle member being located above said rod so as to break an electrical circuit when the normal flow oi the liquid is reduced.

5. A liquid fiow interlock comprising anem closing chamber, an orifice within said chamber, a housing above said orifice, a rod supported within said housing andlocated above said orifice, so as to be actuated by the flow of said liquid, a floating member secured to the lower end of said rod, an insulating element located in the up- .per portion of said housing, depending means supported from said insulating element, a pivoted enclosed liquid conducting switch being arranged so as to be actuated by said rod to break an electrical circuit when the normal flow of the liquid is reduced to a predetermined value. I

6. A liquid fiow interlock comprising an enclosing chamber, an orifice within said chamber, a housing above said orifice, a rod supported within said housing and located above said orifice, so as to be actuated by the fiow or said liquid, a floating member having a cone-like end secured to the lower end of said rod, an insulating ele ment located in the upper portion of said hous= ing, depending means supported from said insulating element, pivoted enclosed liquid conducting switch being arranged so as to be actuated by said rod to break an electrical circuitwhen the normal fiow of liquid is reduced to a predetermined value. 4

7. A liquid fiow interlock comprising an enclosing chamber, an orifice within said chamber, a housing above said orifice, a metallic rod within said housing, a glass rod secured to the upper end of said metallic rod, said metallicrod located above said orifice so as to be actuated by thefiow of said liquid, a floating member secured to the lower end of said metallic rod, an insulating element located in the upper portion of said housing, depending means supported from said insulating element, a pivoted enclosed liquid conducting switch being arranged soas to be actuated by the glass rod portion of said metallic rod to break an electricalcircuit when the normal flow of the liquid is reduced to a predetermined value.

8. A liquid flow interlock comprising an enclosing chamber, an orifice within said chamber, a housing above said orifice, a metallic rod within said housing, a glass rod secured to the upper end of said metallic rod, said metallic rod located above said orifice so as to be actuated by the flow of said liquid, 9. floating member having a cone-like end secured to the lower end of said metallic rod, an insulating element located in the upper portion of said housing, depending means supported from said insulating element, a

pivoted enclosed liquid conducting switch being arranged so as to be actuated by the glass rod portion of said metallic rod to break an electrical circuit when the normal flow of liquid is reduced to a predetermined value.

GEORGE LmDInE'i USSELEJAN. 

